The invention relates to a distribution connection method of an optical cable and an optical communication device. The method comprises the following steps: A, installing a clamping plate in a distribution box; B, installing an optical cable terminal box in the distribution box; C, striping and welding the optical cable; D, installing and connecting an ONU device and a splitter; and E, fixedly installing the distribution box. Compared to the prior art, the method provided by the invention solves the problem of cable chaos in an ONU casing, improves the operability of the casing and facilitates daily maintenance. An optical terminal box provided with a multi-core bunched pigtail fiber and a flange connector is installed in advance, the optical cable welding process can be simplified, errors are not caused during fiber-cable welding and pigtail fiber jumper connection, the welding time is greatly shortened, the work efficiency is enhanced, through a clamping force formed between the hard clamping plate and the backboard of the distribution box, optical communication devices with different specifications can be firmly and reliably fixed in the casing, and the problems of incapability of unified fixation due to diverse specifications, dimensions and installation modes of ONU devices and splitters which are produced by various communication manufacturers are solved.