A sample processing system and a sample processing method for a trace detector are disclosed. The system comprises a sampling substrate for collecting a substance or substances from the surface of an object to be tested by contacting the sampling substrate with the surface of the object, and a trace detector. The trace detector includes a sample feeding device provided with a sample feeding part. The substance collected by the sampling substrate can be transferred to a surface of the sample feeding part so that the substance transferred to the surface of the sample feeding part can be detected. With the configuration of some embodiments of the present invention, a sampling substrate made of chemical fiber is used to collect a sample from the surface of an object to be tested by contacting the sampling substrate with the surface of the object to be tested. The sample collected by the sampling substrate is mechanically transferred to a metal film or mesh of the sample feeding device of the trace detector. Then, the metal film or mesh of the sample feeding device is heated to vaporize the sample and to release the sample vapor into the trace detector. Therefore, the efficiency of sample collection and desorption processes can be improved. In addition, the direct heating of a sampling substrate can be avoided so as to decrease the interference of the sampling substrate with trace detection.