A thin， large aperture， high gain towed line array with weak fiber Bragg gating hydrophones is proposed. A weak fiber Bragg gating array with the same reflectivities， central wavelengths and wide 3 dB bandwidths is selected according to the principle of matched interference， and the grating spacing of the weak fiber Bragg gating array is determined according to the principle of underwater acoustic sensing for 5~10 Hz very low frequency underwater acoustic signals detection. Central wavelengths of the weak fiber Bragg gating array are uniformly shifted and the grating spacing is basically unchanged when the weak fiber Bragg gating array is coated by an optical fiber coating machine. Kevlar and polyurethane protective sheath are laid outside the weak fiber Bragg gating array by an yarn binding machine and sheath machine to form hydrophone towed array. The sound pressure-phase sensitivities of the towed linear array hydrophone unit are measured as -136.97 dB （1 rad/μPa） @ 5 Hz、-139.64 dB @ 7.5 Hz、-139.36 dB @ 10 Hz. The self noise power spectrum of the hydrophone caused by flow noise is analyzed， and the spectrum value is in the range of 45~95 dB （1 μPa²/Hz） in the frequency band of 1~100Hz under 8m/s towing speed. The experimental and analytical results show that the proposed towed line array has high sensitivity and low flow noise in very low frequency band， which is expected to increase the detection function of very low frequency underwater acoustic signals for unmanned aerial vehicles.