A large-aperture laser frequency multiplication conversion and focusing device with a crystal temperature regulating and control function solves the problems that large-aperture laser frequency multiplication conversion and focusing devices in the prior art do not have the temperature regulating and control function and cannot achieve non-critical phase matching. A focusing lens, an adapting flange, a quadruple frequency conversion module, a first light pipe, a double frequency conversion module and a second light pipe are arranged from left to right one by one. The focusing lens is fixedly connected with the adapting flange which is fixedly connected with the quadruple frequency conversion module fixedly connected with the first light pipe. The first light pipe is fixedly connected with the double frequency conversion module which is fixedly connected with the second light pipe. The quadruple frequency conversion module and the double frequency conversion module are fixed on a support. The quadruple frequency conversion module employs dual temperature control technology to achieve conversion from double frequency to quadruple frequency. The focusing lens achieves focusing of high-energy laser. The device is used for frequency multiplication conversion of high-flux large-aperture laser.