The invention discloses a fiber grating pulse heating-based soil matric suction quasi-distributed in-situ measurement method and apparatus, including a heating direct current power supply, a high temperature-sensitive insulation tube (in which a resistance wire and a fiber grating are built), a clay bar, and a fiber grating demodulator, and a computer for analyzing and processing monitoring data.A matric suction sensor that is manufactured and pre-saturated is buried in measured soil, and then left to stand for 24 hours to achieve a water potential balance between the clay bar and the soil. The heating power supply is connected to perform pulse heating on the resistance wire built in the matric suction sensor, and heat is diffused, through the high heat-sensitive insulation tube with goodheat conduction performance, into the clay bar wrapped by the high heat-sensitive insulation tube. The fiber grating built in the high heat-sensitive insulation tube is sensitive to a temperature change, and a temperature change value can be obtained by converting fiber grating wavelength data collected by the fiber grating demodulator. Finally, a function relationship between matric suction of the clay bar and the temperature change value is established through a calibration test, and then soil matric suction corresponding to the temperature change value is obtained according to the water potential balance. In the measurement method, the temperature change value is obtained through the thermal pulse heating, and the soil matric suction under a sensor water potential balance condition isobtained according to a calibration relationship between the matric suction and the temperature change value. The invention can realize fast, continuous, remote, high-precision, quasi-distributed soilmatric suction measurement.