A data processing method for a computer system is provided. The computer system includes a host and an open-channel solid state drive. The open-channel solid state drive is connected with the host. The data processing method includes the following steps. Firstly, plural block characteristic parameters of a specified block in a non-volatile memory of the open-channel solid state drive are collected. Then, the plural block characteristic parameters are inputted into a prediction function, so that a prediction value is acquired. If the prediction value exceeds a threshold value, a data in the specified block of the non-volatile memory is moved to a blank block of the non-volatile memory by the host.