The invention discloses a test method of karst water burst when tunneling, comprising the following steps of: preparing materials; filling materials; embedding elements; embedding a water tank; injecting water and monitoring, tunneling and monitoring, etc. The invention further discloses a monitor device used for the test method of the karst water burst when tunneling, comprising a module frame fixed on a base, a preset water tank, a water pressure loading mechanism, a stress field monitoring mechanism, a deformation field monitoring mechanism, a temperature field monitoring mechanism, a seepage field monitoring mechanism, an acoustic emission field monitoring mechanism, a module surface displacement deformation observing mechanism, a module deformation and water burst observing mechanismin tunnels after tunneling, a fiber demodulation device and a computer. The invention simultaneously can research the change regularity of premonitory multi field information which induces the water burst when tunneling at different water body containing positions and under different water pressure conditions, has wide application, high reliability, abundant collecting data, high test precision, etc.