The invention relates to a method for separating serum. The method comprises the following steps of: 1, providing blood collection tubes in which blood specimens are arranged, and heating the blood specimens in the blood collection tubes by using a constant temperature gas bath to make the temperatures of the blood specimens reach 37 DEG C; 2, grabbing the blood collection tubes by using mechanical hands; 3, automatically measuring the weight of the blood collection tubes, and recording the weight; 4, comparing the total weight of centrifugal canisters which are provided with the blood collection tubes and are symmetrically arranged on both sides, and placing the blood collection tubes on the lighter centrifugal canister; 5, calculating the total weight of the centrifugal canisters which are provided with the blood collection tubes; 6, placing the blood collection tubes into the two symmetric centrifugal canisters, and then calculating the weight difference of the centrifugal canisters on both sides; 7 selecting a counter weight of which the weight approaches to the weight difference of the two centrifugal canisters from standard counter weights, and putting the counter weight on the lighter side; 8, repeating the step 2 to the step 7 to complete the weighting of all the centrifugal canisters; 9, automatically centrifuging; 10, grabbing the centrifuged blood collection tubes out of the centrifugal canisters by using the mechanical hands, placing the blood collection tubes on an uncapping station, and putting the counter weights back; and 11, automatically uncapping the blood collection tubes. The invention also discloses equipment for automatically separating the serum.