The Cuban government has begun a massive campaign of anti-U.S. popular mobilization, including island-wide demonstrations and calls for expansion of provincial militias, in response to what it has called "hysterical anti-Cuban allegations" by U.S. officials during the past 10 days.

The campaign began with long front-page editorials Tuesday and Wednesday in the Communist Party newspaper Granma denouncing a May 20 speech by President Reagan to Cuban exiles in Miami and a statement last Sunday by Sen. Barry Goldwater (R-Ariz.) that the Cuban problem should have been solved by U.S. invasion and annexation.

Anti-Cuban statements have been relatively common in the Reagan administration, and heretofore largely ignored by the government of President Fidel Castro. The Cubans have chosen a harsh public response now, according to Cuban officials, because of what they describe as a crescendo of U.S. "aggression" and criticism that can no longer be ignored.

The Reagan speech seems to have particularly irritated the Cuban government because it was made in Miami before Cuban-Americans who are among Castro's most vehement critics and include veterans of the Bay of Pigs invasion of Cuba. In addition, the address came on the 81st anniversary of Cuban independence from Spain, which in the Cuban perspective marked the opening of U.S. domination over the island.

Goldwater's subsequent television interview, suggesting that the United States would be better off with Cuba as its 51st state, also touched a raw nerve here. It recalled the decisive U.S. role in Havana before Castro's 1959 revolution and the U.S.-sponsored Bay of Pigs attack in 1961 that the government repeatedly cites as an example of what could happen again.

This suggestion has been reinforced recently by U.S. backing for Nicaraguan guerrillas fighting to overthrow the Sandinistas in Managua.

The Cuban government has announced no change in foreign policy, and there is no indication that it plans a direct response to the United States. At the same time, Castro himself has remained silent and out of public view during the past week.

But for what appears to be a combination of internal political reasons--a need for periodic revitalization of revolutionary spirit in the population--and a genuine concern that administration rhetoric has reached such a pitch that its threats might become reality, a series of responses was set in motion.

The first Granma editorial, "Imperialist Hysteria," was unusually long, taking up half the front page and two-thirds of page two. Carefully organized, it sought to rebut point by point Reagan's charges concerning Cuban labor unions, foreign military involvement, economic difficulties, official participation in drug smuggling and the status of Miami's Cuban exile community.

In a pointed reminder, the party organ also said that Reagan's appearance in Miami marked the first time a U.S. president has addressed Cuban-Americans there since 1962, when John Kennedy "received from the defeated invaders a flag that was not precisely covered with glory and promised to return it to Havana."

The editorial then questioned Reagan's leadership and charged his speech was at once an electoral maneuver aimed at Hispanic voters and a real threat to Cuba.

"The mediocre electoral spectacle of May 20, in spite of its burlesque falseness, carries a threat that we cannot ignore," it went on. "It is not exactly lucidity and realism that dictate Ronald Reagan's conduct. Once again he demonstrated to what extremes he is ready to descend. In his hysterical arrogance, Ronald Reagan is capable of any adventure . . ."

Referring to U.S. charges repeated by Reagan in Miami that Cuban officials have been involved in drug trafficking to the United States, the editorial added: "It is frankly unbelievable that the president of a country where the proliferation of social afflictions such as drug addiction, prostitution in all its forms and degenerations such as generalized pornography would make Sodom and Gomorrah blanch, should accuse Cuban officials--and by extension our government--of promoting drugs that do not need promotion in the United States."

The following day, reacting to Goldwater, Granma published a still more strongly worded editorial portraying the senator's reference to invasion as a reflection of Reagan's foreign policy, and therefore, as a threat to Cuba comparable to Hitler's threat to gobble up Austria before World War II.

"The very appearance of this personage from the caves in a star spot on one of the main U.S. television networks, acting as an echo to Reagan and his hysterical anti-Cuban allegations before the Miami worms, demonstrate that it is precisely these ideas that steer present U.S. policy and impregnate the virulent propaganda campaign with which the Yankee administration is trying to justify its warlike, interventionist and arrogant actions in Central America," it said.

Taking their cue from Granma, Communist Party and government officials around the island organized mass protests. Granma and provincial newspapers published front-page photographs of protesting crowds carrying banners denouncing Reagan and the United States. The national radio reported a flood of telegrams with similar protests.

At one rally of about 8,000 persons Friday in Holguin in eastern Cuba, the provincial party leader announced that the strength of the province's Territorial Troops Militias would double in reaction to Reagan's "imperialist madness."

"Let the imperialists know that when our arms are insufficient, we will seize arms from those who seek to invade us," said Miguel Cano Blanco, first secretary of the provincial party apparatus and alternate member of the national party Politburo. "All the people must prepare for the war of all the people."

The militias, said officially to number half a million, were formed three years ago to provide regular military training for Army veterans, students, workers and women.