We present a new method for the detection of double-lined spectroscopic binaries (SB2s) using Vsini values from spectral fits. The method is tested on synthetic and real spectra from the Large Sky Area Multi-Object fiber Spectroscopic Telescope Medium Resolution Survey. It can reliably detect SB2 candidates for double-lined binaries with Vsini1+Vsini2<300km/s if the radial velocity separation is large enough. Using this method, we detected 2460 SB2 candidates, 1410 of which are new discoveries. We confirmed the correlation between the radial velocity separation estimated by the binary model and Vsini0 estimated by the single- star model using the selected sample. Additionally, our method found one new SB2 candidate in open cluster M11.