Generalized coherent states of a non harmonic oscillator in a finite dimensional Hilbert space are constructed and some quantum statistical properties are studied. Their squeezing effect and antibunching effect are discussed in detail. The condition of squeezing is found, and the relation between antibunching effect and the dimensionality of the Hilbert space is shown by using numerical calculation. Theoretical calculation shows that the coherent states present squeezing effect and antibunching effect, and these quantum statistical properties are very different from those of usual generalized coherent states in infinity dimensional Hilbert space.