The present invention pertains to the field of medical technology, and particularly relates to a heterocyclic substituted pyrimidine compound represented by General Formula (I) and its pharmaceutically acceptable salt thereof, wherein R1, R2, R3, R4 and R5 are as defined in the description, the present invention also relates to a preparation method of the compound, a pharmaceutical composition containing the compound, and a use of the compound and the pharmaceutical composition in preparation of a medicine for enhancing a cGMP signal transduction function or a medicine for treating or preventing sexual dysfunction and diseases with lower urinary tract symptoms.
