The invention discloses a method and a system for sampling a network field intensity. The method comprises the steps of obtaining a distance interval between every two sampling points of an LTE-R network field intensity according to a lee's sampling criteria; calculating a pulse number, which needs to be obtained when every sample is collected and is output by a speed pulse sensor on a train wheel, according to the distance interval; and performing sampling on the LTE-R network field intensity according to the calculated pulse number. Through the scheme of the invention, an LTE-R network coverage testing result can be guaranteed to meet probability requirements on a time and a place when the coverage of the LTE-R network field intensity is 95%, the effect that a sampling frequency of the LTE-R network field intensity is dynamically adjusted according to a train speed is achieved, and the collected field intensity data are guaranteed to include all slow fading and partial fast fading information.