A towrope type ocean controllable source electromagnetism and earthquake data collection system is composed of electric field sensors (non-polarized electrodes) distributed in three or more towropes uniformly or not, three-component induction coil type or three-component fluxgate type magnetic field sensors and sonic sensors composed of hydrophones or accelerometers and is used for measuring ocean three-component magnetic-field components, electric field components EX distributed in the cable direction, electric field components EY distributed in the vertical cable direction and ocean earthquake data. The towrope type ocean controllable source electromagnetism and earthquake data collection system can collect ocean electromagnetism data and ocean earthquake data in the time domain and the frequency domain at the same time, increase the collection quantity of ocean geophysics data of advancing construction at a time in a multiplying mode, effectively improve the target detection precision and explore and evaluate ocean mineral products, oil and gas resources and methane hydrates through combination and comprehensive application of ocean controllable source time-frequency electromagnetism and the earthquake exploration technology.