The invention discloses a cable-free netsonde for fishing of a small trawler. The cable-free netsonde comprises net rope sensors, net plate sensors and a control end; the control end is arranged in a driving cabin of the trawler, the control end comprises a communication assembly and processing equipment, and the processing equipment is in communication with the net rope sensors through the communication assembly, receives data sent by the net rope sensors and performs processing; the net plate sensors are arranged on trawlnet net plates of the trawler, and are used to acquire net plate state data and send the net plate state data to the net rope sensors in a water sound communication manner; the net rope sensors are arranged trawlnet net ropes of the trawler, and are used to acquire net rope state data and obtain the net plate state data of the net plate sensors; and the net rope state data and the net plate state data are transmitted together to the control end by the net rope sensors. The cable-free netsonde is used to perform working state measurement of the net plates and the net ropes and perform working state measurement of a trawlnet.