Combined with the soil conditions of water chestnut planting field and the existing manual harvesting methods， a self-propelled water chestnut harvester for harvesting with water was designed to solve the problem of the high labor intensity of water chestnut harvesting and the lack of harvesting machines that can be used in practical production. The machine is composed of walking system， transmission system， rotating disturbance device， lifting and separation device， collection device， etc. It can conduct the excavation of water chestnuts， separation of fruit and soil， lifting and collection of water chestnut and other work at one time. The transmission system of the whole machine is divided into hydraulic transmission part and mechanical transmission part. The hydraulic transmission part provides power for the walking system of the harvester and the digging and harvesting device， which can realize the walking speed control of machines， the height adjustment of the digging and harvesting device， the speed control of the rotating disturbance device and the speed control of the lifting and separation device. The mechanical transmission part provides a stable speed difference between the rotating disturbance rollers at all levels and the lifting and separation device to ensure the smooth progress of the harvesting process. The three-stage rotating disturbance roller forms a rotating disturbance device to realize the full disturbance and mixing of soil and water. The toothed digging shovel and lifting chain form a lifting and separation device to perform the excavation of water chestnut fruits， the separation of fruit and soil and lifting of water chestnut fruits. The performance of the track chassis of this type of water chestnut harvester was analyzed theoretically. The results showed that the theoretical minimum steering radius of chassis differential steering， the theoretical steering radius of in-situ steering， the theoretical value of the uphill limit overturning angle， and the theoretical value of the downhill limit overturning angle was 1.5 m， 1.0 m， 55.63° and 55.08°， respectively. It is indicated that the machine has small turning radius and large ultimate overturning angle， which is very suitable for the working environment of water chestnut planting field. The results of the field trial showed that the maximum driving speed of this type of water chestnut harvester on the field road， the minimum steering radius of differential steering the in-situ steering radius， the maximum climbing angle， the fruit digging rate， and the damage rate under the experiment conditions is 0.97 m/s， 2.1 m， 1.3 m， 24.2°， 53.19%， and 4.21%， which can meet the performance requirements of water chestnut mechanized harvesting to a certain extent.