The invention relates to a method for safely identifying an effective user of a combined source channel in the wireless communication field. The method combines safety with identification, embeds a random and recognizable head mark related to the source channel data into the starting part of each packet during the modulation of the baseband digitals, adopts encryption-based protection for the head mark ascertained by the packets to improve the safety of the source channel, and makes effective user identification for the head data using multi-signal sorting based on subspace in receiving. After the method for safely identifying an effective user of a combined source channel is adopted, the safety of the packet transmission in the source channel can be improved, and the transmitted packets are hard to be intercepted and interfered; solving the problem of packet collision, the method also realizes the identification of the effective users to improve the missed alarm possibility. After identification, the method does not need to de-spread all the packets and just de-spreads the packets of the effective users; therefore, the decoding load is reduced and the unnecessary energy consumption of a receiver can be reduced to save the limited battery energy.