Wolfgang Amadeus Mozart (1756-1791) was one of the important composers of the eighteenth century. In his works, he was endowed with innate talent, children’s innocence and intelligent, adult humorous and persistent. Because of conflict and contrast on Mozart's distinctive personality, the music he composed are full of dramatic tension. The content, scope and texture of his instrumental works are still the standard of composition.

For Mozart's musical character, it can be defined by "Ambiguity". Human daily language cannot accurately describe the feelings that music brings to us, but Mozart’s music appears the unspeakable joy with sadness, and those indescribable laughter with tears in our life.

In only 35 years, he has composed more than 600 works, including 27 piano concertos. Most of Mozart's piano concertos are clear in major tonality. Only "Piano Concerto No. 20" (K. 466) and "Piano Concerto No. 24" (K. 491) in minor tonality. This thesis takes "Piano Concerto No. 21 in C Major" (K. 467) and "Piano Concerto No. 24 in c Minor" (K. 491) as examples to analyze and compare the character and characteristics of Mozart's music.