The invention discloses a serial-resistance type infiltration range measuring device of two sides of a river and a measuring method thereof. The measuring device comprises serial-resistance type soil moisture sensors, cohesionless soil transition layers, a ground temperature sensor, and the like. A row of vertical measuring holes are drilled in the ground in an equidistant mode on the two sides of the river in the direction perpendicular to the water flow direction of the river respectively, one serial-resistance type soil moisture sensor is inserted in the center of each measuring hole, the cohesionless soil transition layers are poured into gaps between the serial-resistance type soil moisture sensors and hole walls of the measuring holes, the top ends of the serial-resistance type soil moisture sensors are flush with the ground, gravel protection layers cover the serial-resistance type soil moisture sensors, and fences and a drainage ditch are arranged on the peripheries of the gravel protection layers. The measuring device is applied to measuring infiltration ranges of soil with different properties on the two sides of the river and can measure the groundwater buried depth, soil dryness and humidity and the ground temperature. The measuring device has the advantages of being high in accuracy, large in measuring range, easy to install, and capable of outputting data of the infiltration range of the two sides of the river in real time, and the measuring device is a novel measuring device capable of utilizing water resources reasonably.