The invention provides a steel wire sensor system for monitoring the well wall and a deformation early warning method thereof. The steel wire sensor system comprises steel wire concrete strain gauges,steel wire pressure gauges, cables, a measuring instrument and a computer. Multiple steel wire concrete strain gauges are arranged on the internal surface of the well wall. Multiple steel wire pressure gauges are arranged in the internal part of the well wall. Multiple steel wire concrete strain gauges and multiple steel wire pressure gauges are connected with the measuring instrument through thecables. The measuring instrument is connected with the computer. The measuring instrument receives the frequency signals acquired by the steel wire concrete strain gauges and the steel wire pressuregauges. The measuring instrument converts the frequency signals into digital signals and transmits the digital signals to the computer. The grouting pressure borne by the well wall, the well wall deformation and the well wall temperature can be monitored so as to ensure long-term stability and reliability of the observation system.