A method, an apparatus and a system for uplink rank adaptation are provided in the present invention, wherein the method comprises: estimating the maximum supportable data rate and channel information of a user equipment in uplink transmission; comparing the maximum supportable data rate with one or more predetermined thresholds, wherein the predetermined thresholds are associated with corresponding ranks; and determining a rank used by the user equipment in the uplink transmission based on a result of the comparison and the estimated channel information. With the present invention, a base station can quickly determine a rank for uplink MIMO transmission, decrease the rank estimating error, and lower the computation complexity for estimating the rank and the subsequent pre-coding vector.