The present invention discloses a method for removing basic nitrogen from crude isopentene. According to the method, crude isopentene passes through a fixed bed reactor formed from sulfonic acid cation exchange resin/water; the water is circulation water from top to bottom, and the water surface is higher than the resin bed layer formed from the sulfonic acid cation exchange resin; the crude isopentene enters the resin bed layer in a countercurrent manner from bottom to top and is subjected to basic nitrogen removing; and the mass exchange capacity of the sulfonic acid cation exchange resin is 3-5.5 mmol/g, the mass space velocity is 3-15 hr<-1>, the reaction temperature is 5-50 DEG C, and the reaction pressure is 0.1-0.6 MPa. According to the present invention, the crude isopentene passes through the fixed bed reactor formed from the sulfonic acid cation exchange resin/water, such that the double functions of basic nitrogen removing and wastewater treatment are achieved, and the method has advantages of simple process, no wastewater emission, high nitrogen removal precision, effective polymerization side reaction prevention, and no material loss.