The present disclosure relates to the technical field of safety detection, and in particular to a sample collecting and introducing device and a detection system. The sample collecting and introducing device provided by the present disclosure includes a sampling device for collecting a sample, and a semipermeable membrane device for extracting the sample collected by the sampling device and conveying the extracted sample to detection equipment, wherein the sampling device is provided with an air guide cavity, the air guide cavity is configured to guide airflow carrying the sample to flow to the semipermeable membrane device, the semipermeable membrane device is provided with a semipermeable membrane which is arranged outside the sampling device. In the present disclosure, the size of the semipermeable membrane is no longer limited by the sampling device, and therefore the difficulty of increasing the area of the semipermeable membrane is reduced.