1. A joint detection reception method, which is utilized irrespective of a length of an orthogonal code in a TD (Time Division)—CDMA (Code Division Multiple Access) mobile communication system, to create a system matrix associated with a joint detection receiver in a same time slot of the TD-CDMA mobile communication system, the method comprising the steps of: a) repeating and partitioning individual channelization codes having variable lengths, and creating channelization code blocks having same lengths; b) performing a convolution operation between the repeated and partitioned channelization code blocks and a channel impulse response, and acquiring combined impulse responses; c) grouping the combined impulse responses to construct sub-block matrices for a joint detection system; and d) arranging the sub-block matrices for the joint detection system to be shifted by a predetermined column distance, and constructing a joint detection system matrix.