Stevenson P. Bryan, a former Montgomery County school system accountant who admitted embezzling nearly $1.2 million for love of his terminally ill wife, will enter the county jail on Valentine's Day to begin serving six months' detention.

At an emotional hearing, during which Bryan wept and read from the Bible and a psychiatrist described him as carrying "a tremendous burden of guilt," Judge John J. Mitchell yesterday sentenced Bryan to five years' imprisonment on each of three theft counts, suspended except for consecutive 30-, 60- and 90-day terms.

Saying, "I will show mercy," Mitchell recommended that Bryan spend only a "turnaround" weekend at the jail beginning Feb. 14, with the six months to be served in the county's work-release center.

Mitchell also sentenced Bryan to five years' probation after his release and ordered that Bryan, 53, complete restitution to the school board by the end of that time. Bryan has already paid back more than $1 million.

Defense attorney Arthur Brisker argued, "This was not a crime motivated by personal greed, this was a violation of law motivated by love. There was no corruption in high places, no obstruction of justice."

But Deputy State's Attorney Matthew Campbell, while conceding that Bryan's cooperation made the case "remarkable," urged the judge to impose a sentence that would deter other criminals.

"I felt that a million-dollar theft required some incarceration," Campbell said after the sentencing.

Bryan's embezzlement, which had not been detected by at least two internal audits, came to light last May when Bryan, a 21-year employe of the school system who administered the medical benefits accounts, turned himself in to the state's attorney. Suicidally depressed, he was admitted to Suburban Hospital for three weeks; and according to Brisker, "may never get over" his guilt.

Bryan supplied prosecutors with documents detailing the scheme and turned over cash and assets, including $600,000 in gold coins, two cars and the deed to a $250,000 farm in Frederick County.

Bryan told prosecutors that after his wife contracted multiple sclerosis, he became obsessed with fears of not being able to provide for her as medical bills skyrocketed.

During a period of five years beginning in 1979, using blank checks that he had been ordered to destroy, Bryan diverted funds by making payments to the nonexistent Montgomery Medical Technical Laboratory, and depositing the checks in dummy accounts. In his official capacity, the canceled checks were returned to him.

His wife died in July 1984. His teen-aged son and daughter are now living with relatives in another state.

In his comments, Judge Mitchell was critical of the school system for not having uncovered the shortfall. Schools spokesman Bill Henry said yesterday that the internal audit controls have been "significantly altered" since Bryan confessed.

At the time Bryan turned himself in, school officials said his admission apparently was triggered by a routine audit undertaken by the Department of Education accounting staff. The auditors requested canceled checks, but on the advice of his attorney, Bryan took them instead to the state's attorney's office and offered his cooperation in the investigation.

The light sentence yesterday was not unexpected. At the beginning of the investigation, State's Attorney Andrew L. Sonner described Bryan as a "typical Bob Cratchit, working away, taking care of his two children and his dying wife." Sonner said that while prosecutors usually considered themselves "hard-boiled," Bryan's plight "touched strings of mercy we don't usually feel."

Bryan still owes more than $57,000; and a school board spokesman said yesterday that the board will try to get the rest of the money from the bonding company that certifies the school system against employe theft.

Last summer, Bryan went to live with a childhood friend, pastor of a Seventh-day Adventist Church in North Carolina, and worked as a bookkeeper for the publishing arm of the church.

Bryan now lives with and works for Roscoe Bartlett, a Frederick Community College professor who also owns a construction firm.

When asked at yesterday's hearing if he had anything to say on his own behalf, Bryan apologized to the school board for the embarrassment he caused and then read a verse from Paul's Epistle to the Ethesians: "Let him that stole steal no more: but rather let him labor, working with his hands."