I have been a PhD student in the Group of Pulsating Variable Stars and Asteroseismology of the Department of Astronomy of Beijing Normal University since September of 2018. My main research topic is classification and analysis of a large amount of stellar spectra provided by the LAMOST-Kepler project. The MK spectral classification system, first developed by Morgan et al. (1943), is the main system for astronomers to classify stars according to their spectra. Spectral types can be used to estimate physical parameters (effective temperature, surface gravity, metallicity), age, distance and spectral shift, and play a key role in many fields of astrophysics. In addition, spectral classification can be used to identify peculiar and interesting stars. MKCLASS is a computer program written in C language. It was developed by R. Gray & C. Corbally in 2014. Under the supervision of Dr. R. Gray, I have improved the MKCLASS program, especially for hot and cold stars. Therefore, in order to verify the effect of the improvement, we classify the spectra provided by the LAMOST-Kepler project and compare the results obtained by the previous version of the program. At the same time, the MKCLASS program is used to search for special stars such as Ba stars, lambda Bootis stars and white dwarfs in the LAMOST-Kepler fields.