The invention provides an in-situ test 
system for mechanical properties of a nano material. The in-situ test 
system comprises a scanning electronic 
microscope, a scanning probe test unit, a 
control unit and a computer; the scanning probe test unit comprises a base, an adjusting table arranged at one side of the upper surface of the base, and a measuring mechanism arranged at the other side of the upper surface of the base; the scanning electronic 
microscope comprises an 
electron microscope pole shoe, and the adjusting table is provided with a sample table, an X-axis adjusting apparatus, a Y-axis adjusting apparatus and a Z-axis adjusting apparatus; the measuring mechanism comprises a 
laser light path adjusting apparatus, a probe foundation support arranged on the base, and a probe arranged on the probe foundation support, the probe is positioned below the 
electron microscope pole shoe, and the 
laser light path adjusting apparatus is used for collimating and focusing 
laser. By adopting the in-situ test 
system and the in-situ test method, an acting process of the scanning probe and a sample and an evolution process of a sample 
microstructure under a physical mechanical function of an 
external field in the test process can be actually observed in site, and micro images of a series event and 
mechanical property test data are transmitted to a computer.