The studies on the selective synthesis of dialkyl selenide compounds 1 were presented. Overcoming the complexity and difficulty of selenides (R-Se-R) and/or multiselenides (R-Sen-R; n ≥ 2), we aimed to optimize the reaction condition for the tolerable preparation of sodium selenide (Na2Se) by reducing Se with NaBH4, and then to achieve selective syntheses of dialkyl selenides 1 by subsequently treating the obtained sodium selenide with alkyl halides (RX). Consequently, various dialkyl selenides 1 were efficiently synthesized in good-to-moderate yields. The investigations on reaction pathways and solvent studies were also described.