Similarities :
(1) The source of both the religion is vedic religion and both and indebted to Upanishads
(2) Both Gautam Buddha and Mahavir belonged to princely families and not to priestly families.
Dis-similarities :
(1) Difference regarding conception Moksha :
According to Buddhism, a man attains Moksha when he ends all the desires and can attain it while living in the world. But according, to Jainism Moksha is freedom from miseries and can be attained only after death.
(2) Means of attainment of Moksha:
According to Buddhist Sangha is proper for attainment of Moksha and they hate self-mortifications and severe penances. Jainism believes in fasts and severest penances.