We conduct a systematic tidal disruption event (TDE) demographics analysis using the largest sample of optically selected TDEs. A flux-limited, spectroscopically complete sample of 33 TDEs is constructed using the Zwicky Transient Facility over three years (from October 2018 to September 2021). We infer the black hole (BH) mass ($M_{rm BH}$) with host galaxy scaling relations, showing that the sample $M_{rm BH}$ ranges from $10^{5.1},M_odot$ to $10^{8.2},M_odot$. We developed a survey efficiency corrected maximum volume method to infer the rates. The rest-frame $g$-band luminosity function (LF) can be well described by a broken power-law of $phi (L_g)propto [(L_g / L_{rm bk})^{0.3} + (L_g / L_{rm bk})^{2.6}]^{-1}$, with $L_{rm bk}=10^{43.1},{rm erg,s^{-1}}$. In the BH mass regime of $10^{5.3}lesssim (M_{rm BH}/M_odot) lesssim 10^{7.3}$, the TDE mass function follows $phi(M_{rm BH})propto M_{rm BH}^{-0.25}$, which favors a flat local BH mass function ($dn_{rm BH}/d{rm log}M_{rm BH}approx{rm constant}$). We confirm the significant rate suppression at the high-mass end ($M_{rm BH}gtrsim 10^{7.5},M_odot$), which is consistent with theoretical predictions considering direct capture of hydrogen-burning stars by the event horizon. At a host galaxy mass of $M_{rm gal}sim 10^{10},M_odot$, the average optical TDE rate is $approx 3.2times 10^{-5},{rm galaxy^{-1},yr^{-1}}$. We constrain the optical TDE rate to be [3.7, 7.4, and 1.6$]times 10^{-5},{rm galaxy^{-1},yr^{-1}}$ in galaxies with red, green, and blue colors.