A planned new purge of Communist Party members in Romania reflects the already ubiquitous role of President Nicolae Ceausescu and his family in running the nation's affairs.

Carried out under the guise of an exchange of party membership cards, the purge is being directed by the president's ambitious wife Elena who is increasingly emerging as a political force in her own right. Earlier this year, she took responsibility for directing Communist Party personnel policy. She has directed that all party members turn in their membership cards to the government, which then evaluates their work and decides who should be allowed to their membership.

The last announced exchange of Communist Party cards in Romania was in 1948 during the Stalinist era when 192,000 party members were expelled. But Western diplomats contacted in Bucharest said there have been several further cases since then and the present purge appears to form part of the preparation for the 12th Romanian Party congress scheduled to open on Nov. 19.

Unlike some other Communist parties in Eastern Europe, which have tried to preserve an elitist image, the Romanian party has aimed at mass membership in line with its attempts to project itself as the guarantor of national independence. At present nearly 2.9 million Romanians belong to the party, including one out of every four workers.

In recent speech, Ceausescu, who has ruled Romania for 14 years, said the exchange of party membership cards was an opportunity to discuss with each and every Communist the way in which he fulfilled his tasks. In effect, all party members are on probation for the duration of the purge during which they will be required to prove their loyalty and obedience to orders from above.

The purge coincides with continuing shakeups of senior government and party leaders in Romania. Part of Ceausescu's highly individualist style of government is to rotate his key aides at regular intervals in order to prevent anyone from building up an independent power base.

The frequency and scope of these reshuffles appears to have intensified during the last year as the 61-year-old leader has tried to defuse mounting political and economic problems. These include a severe blow to the powerful security services last year when Gen. Ion Pacepa defected to the United States and popular discontent at the lowest living standards in Eastern Europe outside Albania.

Ceausecu's response to these difficulties has been to rely more and more on his own considerable family network, which already controls many leading positions in Romania. Apart from his wife, who occupies key party posts and was promoted to the Cabinet in July, other members of the Ceausecu clan include his brothers-in-law Ilie Verdet and Manea Manescu (present and former prime ministers), his nephew Cornel Burtica (deputy prime minister), and his son Nicu Ceausescu (head of the Communist youth organization).

During nationwide celebrations marking Elena Ceausecu's 60th birthday last January, the former chemist was described as "the most just woman on earth" and "the legendary mother from the fairy tales of our childhood." Similar epithets have been bestowed on Ceausecu in one of the most thorough-going personality cults in present-day Eastern Europe.

The significance of the present purge for Ceausecu's personal position is not entirely clear. Some analysts believe it is too cumbersome an instrument for use against senior party figures who have offended him: They can, in any case, simply be dismissed if they step too far out of line.

A senior Western diplomat in Bucharest remarked: "In a mass party such as the Romanian, I see the exchange of party cards as a fairly normal process. This is the mechanism they would use to prune back some of the more marginal and not very active low-level members."

Other analysts point out that the November party congress is likely to confirm Ceausescu's policy of stringent economic austerity into the 1980s. Implementing such a policy in the face of rising consumer dissatisfaction will above all require a disciplined party organization.

The domestic popularity that Ceausescu earned by refusing to support the Soviet-led invasion of Czechoslovakia in 1968 largely has been dissipated. Ordinary Romanians have discovered that, for all the fanfare with which it has been received abroad, their country's independent foreign policy has not led to any substantial improvements in their own lives.