The D.C. Court of Appeals, in a 2-to-1 decision, reversed yesterday the perjury conviction of controversial millionaire landlord Dr. Shao Ti Hsu because Hsu was not fully informed of the consequences of his decision to waive his right to have an attorney defend him against the charge.

In its opinion, the majority noted that Hsu, who holds a doctorate degree in engineering, has "extensive experience" defending himself in numerous landlord-tenant, housing code and traffic court cases.

However, Judge John Ferren, writing for the majority, said that experience may have "misled" Hsu into believing he could defend himself against the more serious perjury charge, which Hsu once described as a trivial matter."

Hsu, a professor at the University of Maryland, at one one time owned hundreds of low-income apartments in the District and Prince George's County. In 1976, city officials characterized Hsu as the single most frequent violator of the District's housing code. Court records indicate that Hsu who lives in Potomac has sold much of his property or transferred ownership to relatives.

In its decision, the appeals court commented that it could not tell from the trial record whether Hsu's decision to act as his own attorney "was a shrewd tactical maneuver, calculated in the event of conviction to achieve" a reversal on appeal - which Hsu won - or whether Hsu "with his extensive but narrow legal experience, was a victim of his own arrogance and ignorance."

Nevertheless, Ferren wrote, the court must reverse the conviction because Judge Tim Murphy, who presided at Hsu's trial in D.C. Superior Court, did not make a sufficient inquiry into Hsu's decision to give up his constitutional right to a lawyer. Ferren was joined in the opinion by Judge John W. Kern III.

Hsu hired lawyers from the prestigious Washington law firm of Williams and Connolly to represent him in the appeals court.

In a strong dissent, Judge Catherine B. Kelly described Hsu as a "gentleman of education, intelligence, confidence and arrogance (who) displayed surprising aptitude" in defending himself against the perjury charge. In the course of his prosecution, Hsu moved to dismiss the indictment, carefully questioned prospective jurors and "exhibited consideration skill" in handling witnesses, Kelly wrote in a separate opinion. Kelly said Hsu understood the nature of the charge against him and said she would affirm the perjury conviction.

"The authorities speak often about the old saying that one who represents himself in court has a fool for a client. It is clear, however, that whatever else he is, Dr. Hsu is no fool," Kelly said.

A Superior Court jury, after 15 minutes of deliberation, convicted Hsu of perjury in September 1976 in connection with his testimony at a civil trial in which he denied receipt of a court order than he make repairs at an apartment building he owned in Southeast Washington.

Murphy sentenced Hsu, then 60 years old, to serve 20 months to eight years in prison. At the time, Murphy told Hsu "You have no respect for the truth. You have no respect for the American justice system. You have spread the cancer of lies and deceit throughout this court unparalleled in my memory. There is not a division of this court that has not suffered from the lies. . ."

John P. Hume, chief of the felony trial section of the U.S. attorney's office, said yesterday that the government will review the appeals court's decision before deciding whether Hsu will be prosecuted again.