The present invention discloses a method for suppressing cross-slot interference in a time-slotted CDMA system. The method includes: determining, by a base station, positions of cross slots according to configuration information of local cell and configuration information of co-frequency adjacent cells, and performing multi-cell channel estimation on the cross slots to obtain channel estimation results; determining, by the base station, code channel configuration information of the co-frequency adjacent cells, grouping the determined code channels and determining the code channels of the co-frequency adjacent cells involved in a joint detection; and performing, by the base station, the joint detection according to the multi-cell information estimation results and the determined code channels of the base stations involved in the joint detection to obtain detection data. With the present invention, interference from a base station transmitting downlink signals in cross slots to a base station receiving uplink signals in the corresponding slot may be reduced, and the system capacity and the stability may be improved.