The invention discloses a submarine optical branch connector box and connecting technology, which comprises the following parts: main cable bending limiter, external pyramid, middle pyramid, conical axle, bearing nut, pushing sleeve, O-shaped coil liner, sealing seat body, support ring, compression ring, locking axle, tray, sealing cylinder, branch line case, branch seat bearing nut, branch seat, locking nut, branch sealing seat and branch binding limiter, wherein the main cable bending limiter, bearing nut, pushing sleeve, sealing component, branch seat bearing nut and sealing seat pierce the main cable end sequently; branch one and two cables pierce the branch binding limiter, bearing nut, pushing sleeve and sealing component.