The invention discloses a river silt detection device, which comprises a silt probe (1), a suction pipe (2), a metering water pump (3) and a photoelectric detector (4), and the metering water pump (3) is installed on the water suction pipe (2) ), the water inlet of the suction pipe (2) is connected to the upper part of the sludge probe (1), the water outlet of the suction pipe (1) is connected to the photoelectric detector (4), and the sludge probe (1) includes a probe cylinder (11), a solenoid valve (12 ) and clean water pipe (13), the solenoid valve (12) is set on the bottom surface of the probe cylinder (11), the clean water pipe (13) is set on the side wall at the bottom of the probe cylinder (11), and the clean water pipe (13) opens to float At least 5 meters, a touch switch (14) for controlling the closing of the solenoid valve is installed on the bottom surface of the probe cylinder (11). The technical effects of the invention are: the thickness of the silt can be accurately measured, the silt is less disturbed, there is no radioactive hazard, the use is safe, the structure is simple, and it is easy to operate and measure.