Abstract: Expansive soil (rock) has special engineering features. The canal slope of expansive soil is instable. It is difficult to deal with the canal slopes of expansive soil. The level of monitoring technology is higher. The selection, layout and laying technology of monitoring equipments as well as the monitoring methods of horizontal displacement, water content, suction, pore water pressure, earth pressure in the canal slopes of expansive soil (rock) are summarized. The stability monitoring of canal slopes shows that the damage of canal slopes of expansive soil (rock) is caused by crack and/or expansion. The monitoring of protection treatment shows that replacement ballasting treatment measure is effective in shallow instability of canal slopes, and water content decreases and fluctuates sensitively with the initial water content being affected by atmosphere. The relationship between suction and water content, the relationship between pore water pressure and water level, variation of earth pressure and other monitoring results are also studied .