The Roman Catholic church, largest Christian faith in Rhodesia, has become caught in a cruel cross fire between the hostile, white-dominated transitional government and suspicious black nationalist guerrillas.

The government yesterday informed the Catholic church that it intends to carry out plans to deport two more of its missionaries. Their departure will bring to 15 the number of Catholic missionaries ousted from Rhodesia on suspicion of having aided the guerrillas.

But ironically, the church has an even worse problem with the guerrillas, who have suddenly made missionaries and their institutions prime targets. The slaying of two German Jesuits 90 miles west of Salisbury Tuesday brought to 18 the number of Catholic missionaries killed so far.

"It's as if the devil has gotten ahold of the country," the Catholic bishop of Bulawayo, Henry Karlan, remarked.

The attacks on Catholic missionaries seem all the more paradoxical since one of the guerrilla leaders, Robert Mugabe, was educated by them and the family of the other, Joshua Nkomo, is mostly Catholic and he himself was once a lay preacher.

Beyond that, the Catholic Church has led a crusade through its Commission for Justice and Peace to bring to light cases of misconduct by the Rhodesian army and has repeatedly embarrassed the Rhodesian government by presenting evidence of torture.

Two of the commission's books, "The Propaganda War" and "Civil War in Rhodesia," have been banned, and the government has acted to stop its investigations by raiding its offices, seizing its papers and prosecuting or deporting its top officials.

One of the latest two missionaries ordered departed, Father Dieter Dernd Rudolf Scholz, was vice chairman of the commission.The other, Father Martin O'Regan, was convicted last fall for failing to report the presence of guerrillas at the Regina Coeli Mission in northeastern Rhodesia and given a suspended three-year prison term.

Yet the guerrillas, for reasons that remain hotly debated, killed more and more of the church's missionaries.

The latest victims were Father Gregor Richert, 48, and brother Bernhard Lisson, 68, who were shot to death Tuesday at St. Rupert's Mission.

The killing of defenseless missionaries has thrown all the churches into a state of extreme anguish and agonizing decision making about the future of their work in Rhodesia.

Across the country, hundreds of other missionaries living in the shadow of death are weighing the most important decision of their lives; whether to leave, or stay and face the very real risk of being shot to death.

Bishop Karlan, interviewed in his office adjacent to St. Mary's Cathedral in Bulawayo, told how he had just finished talking to the last missionary remaining at a lonely mission near the Botswana border where guerrillas are extremely active.

The missionary, he said, had made his decision to stay and die with his flock if that was God's will.

He said the Catholic church had made no decision whether to order all missionaries out of the countryside, and said he had been agonizing over what to counsel the remaining 21 missionaries and doctors and 26 sisters in his own diocese.

"I have told them all that each person must make his own decision," he said.

In addition to the lives of 50 people, Bishop Karlan now has millions of dollars of abandoned property to worry about in his diocese, a problem common to all the missionary groups that have had to pull out of some stations.

Many of the missions have thousands of acres of farm land and large herds of cattle in addition to schools, hospital and clinics.

There has been some talk of bringing in security forces to guard the mission sites. The local newspaper, the Rhodesian Herald, reported yesterday that a midwestern American group, the Church of Christian Liberty, was offering to send a private paramiltary force to reopen the Mission where 12 missionaries and their children were axed and clubbed to death.

The 12 were buried in a small cemetery at the foot of the Vumba Mountains yesterday following that church officials described as a thanksgiving service.

"For them, their cares are over," declared the Rev. John Smyth, British secretary of the Elim Pentecostal Church. "They will feel no more the terrors of the night in the mountains of Rhodesia."

The director of the American church that has proposed reopening their mission, the Rev. Paul Lindstrom, was quoted by the Rhodesia Herald as saying he envisaged the project as being "like the days of the Wild West in which all the mission staff would have both a bible and a gun."

But this approach is clearly repugnant to most missionary groups here. Bishop Karlan, for example, ruled this out. "We don't want to do missionary work under the protection of the security forces," he said.

Bishop Karlan himself is facing a dangerous trip next week to a remote mission for a confirmation ceremony and realizes he could be killed by guerrillas as his predecessor, Bishop Adolph Schmitt, was slain in December 1976.

"My policy as bishop is no arms, and I personally will never take a weapon along," he said.

The attacks on the missions are presently concentrated in Western Rhodesia, where guerrillas of Nkomo's Zimbabwe African People's Union (ZAPU) seem to have adopted a policy of forcing all schools to close down.

Whether it is also ZAPU policy to kill the missionaries is less clear. In some instances the guerrillas have visited mission site and ordered schools to shut down without killing anyone. However, the latest two missionaries killed at St. Rupert's were gunned down by guerrillas speaking Sindebele, the language of the Ndebele who support only ZAPU.

One Catholic missionary theory is that their fate in any encounter with the guerrillas depends on where the individuals were trained. Those sent away to Cuba, the Soviet Union or Eastern European countries for training and indoctrination are mainly responsible for the killings, according to some missionaries, while those who remained in Zambia are less brutal, anti-church and anti-white.

However, other missionaries feel it is just a question of the length of training and degree of discipline. They assert the killings are mostly the work of bandit groups who obey only their immediate leader.