A method, an apparatus and a system for estimating channels are disclosed. A method for estimating channels includes: receiving, by a User Equipment (UE), downlink signals sent by two or more Access Points (APs), wherein no common reference signal is comprised in any data channel symbol domain except a preset symbol domain in the downlink signals; and performing, by the UE, channel estimation according to the downlink signals. The technical solution disclosed herein eliminates the interference between the reference signal and the data signal, enables the UE to estimate the channel value between the UE and the cooperative APs accurately, and improves the UE performance.