Investigation results on ultrashort pulses of a passively mode-looked Nd glass laser are presented in this article. The generation, selection and amplification of the ultrashort pulses are described in particular. The effects of dye cell, dye concentration and the transmissivity of the output mirror on mode locking have been studied. The amplification factor and the signal-to-noise ratio for pulses of 10 ps to 130 ps have been measured. Some of the experimental results on interaction between ultrashort pulses and plasma are also included.