President Reagan returned to the White House yesterday, ready to begin a series of briefings on his fiscal 1989 budget and prepare for his State of the Union address.

With the 100th Congress still in recess, Reagan faced a lighter-than-usual workload on his return from a traditional year-end vacation stay at the southern California estate of publisher Walter Annenberg.

White House spokesman Marlin Fitzwater said administration budget director James C. Miller III will begin briefing the president Tuesday on the new federal spending blueprint that he will submit to Congress in mid-February.

Fitzwater said Reagan also has arranged a series of meetings between the National Security Council and the Economic Policy Council to review U.S.-Japanese issues in advance of a Jan. 13 visit to Washington by Prime Minister Noboru Takeshita.

The presidential spokesman said a commission headed by financier Nicholas Brady will present to Reagan on Friday its assessment of the stock market in the aftermath of the Oct. 19 Wall Street crash.

The next few weeks also will find Reagan and his advisers charting an agenda for the home stretch of his presidency, to be outlined in his Jan. 25 State of the Union address.

Top among the priorities for 1988 will be arms control: winning ratification of the Intermediate-Range Nuclear Forces Treaty and pursuit of an agreement to reduce arsenals of long-range nuclear weapons by 50 percent.

Fitzwater said Reagan will have an "awfully busy" spring travel schedule, with four summits already on his agenda. Reagan plans to go to Cancun, Mexico, in mid-February for an annual meeting with President Miguel de la Madrid.

Sometime after that, the president plans to meet Canadian Prime Minister Brian Mulroney in Canada. Reagan and Mulroney signed an historic free trade agreement Saturday in separate ceremonies in Palm Springs, Calif., and Ottawa.

Reagan also is scheduled to hold another round of summit talks in Moscow with Soviet leader Mikhail Gorbachev, perhaps in late May, and hopes to be able to sign a long-range strategic arms agreement at that time.

Reagan also will attend his eighth economic summit meeting with Western industrial leaders, this time in Toronto in June.