The invention discloses a stereoscopic limiting type photovoltaic module supporting and connecting device and an installation method. The device comprises rear struts, front struts and limiting pieces, wherein the rear struts and the front struts are installed on supports or floating bodies of a photovoltaic power generation system. Installation grooves for insertion of the rear ends of photovoltaic panels are formed in the middle portions of the rear struts. Each front strut comprises a horizontally-arranged supporting board and a perpendicularly-arranged rear baffle. The middle portions of the photovoltaic panels are placed on the supporting boards. A supporting screw for the rear end of the corresponding limiting piece to penetrate is arranged above the corresponding supporting board. Pressing blocks are arranged at the tops of the front struts and matched with the supporting screws, and the limiting pieces and the photovoltaic panels are pressed tightly and fixed. The front end of each limiting piece is provided with a limiting steel sheet. The inner side of each limiting steel sheet abuts against the front end of the corresponding photovoltaic panel. The device has the beneficial effects of being easy to install, low in cost, good in stability, long in service life, especially suitable for supporting and connecting different water surface photovoltaic modules and the like.