SAN FRANCISCO, DEC. 27 -- Jerry Rice, San Francisco's record-breaking wide receiver, caught two touchdown passes early and Joe Montana returned to action with a pair of second-half scoring passes tonight as the 49ers overpowered the Los Angeles Rams, 48-0, to claim the NFC West title.

Rice finished the regular season with 23 touchdowns, 22 on receptions and one rushing. That left him one short of the NFL single-season record of 24 touchdowns set by Washington Redskins fullback John Riggins in 1983.

Rice set league records with his 22 scoring receptions and also by catching touchdown passes in 13 consecutive games. He caught three passes for 90 yards today to set a team scoring mark, finishing the regular season with 138 points.

The 49ers finished with a 13-2 record, best in the NFL, and won the NFC West crown for the fifth time in seven years, edging the New Orleans Saints. They will open the playoffs at home on the weekend of Jan. 9-10 against either Washington or the Minnesota Vikings, depending on the outcome of next week's Vikings-Saints wild-card game.

The Rams (6-9) suffered their first losing season in five years under Coach John Robinson.

Steve Young threw for three touchdowns and 174 yards in the first half. Montana, testing the hamstring he injured two weeks earlier, seemed nimble as ever and finished the season with a club-record 31 touchdown passes. L.A. Rams 0 0 0 0 0 San Francisco 13 14 7 14 48 First Quarter

SF -- Craig 1 run (kick failed), 5:49

SF -- Rice 22 pass from Young (Wersching kick), 12:03 Second Quarter

SF -- Rice 50 pass from Young (Wersching kick), 2:55

SF -- Wilson 7 pass from Young (Wersching kick), 9:02 Third Quarter

SF -- Frank 11 pass from Montana (Wersching kick), 9:13 Fourth Quarter

SF -- Wilson 46 pass from Montana (Wersching kick), :18

SF -- Taylor 26 fumble recovery (Wersching kick), 11:49

A -- 57,950

Rams 49ers First downs 9 23 Rushes-yards 31-121 40-149 Passing yards 24 278 Return yards 32 49 Passing 6-18-1 16-22-0 Sacked-yards lost 3-26 1-3 Punts-average 7-44 5-39 Fumbles-lost 2-1 2-0 Penalties-yards 2-20 1-10 Time of possession 26:22

RUSHING -- Los Angeles: White 21-95, R. Brown 1-11, Evans 3-10, Francis 5-10, Dils 1-(minus 5). San Francis

PASSING -- Los Angeles: Dils 5-17-1, 50 yards, Millen 1-1-0, 0. San Francisco: Young 10-13-0, 174, Montana

RECEIVING -- Los Angeles: Ellard 2-24, R. Brown 2-22, Hill 1-4, Tyrrell 1-0. San Francisco: Frank 5-74, Ric