In view of the problems of water leakage and structural damage in the tunnel, to find out the location of high water pressure leakage point or imminent leakage, and to quantify the water pressure, the indoor model pressure test of cracked concrete was carried out to simulate the seepage of cracked lining under different water pressure conditions. The temperature distribution of the seepage surface of concrete block was observed by infrared thermal imaging camera to study the correlation between seepage pressure, the size of the crack and temperature. The experimental results are as follows: the seepage volume is proportional to the width of the crack and the water pressure. Under the same crack conditions, the higher the water pressure is, the faster the seepage velocity is. Under the same water pressure conditions, the more the crack develops, the greater the seepage velocity becomes. The seepage area of the non-penetrating crack seepage surface is often larger than the seepage area of the penetrating crack seepage surface. The temperature is usually the lowest at the maximum seepage flow, so the minimum temperature point in the tunnel seepage area can be found by using infrared thermal imaging camera scanning to determine the most suitable punching and pressure relief position.