A database is founded to estimate the nonlinear impairments of single channel return-to-zero (RZ) transmission systems with arbitrary parameters. Our link setup consists of multi-span transmission fiber and dispersion compensation component, with dispersion slope full compensating. The total transmission distance and the transmission fiber could be arbitrary, i.e. with arbitrary nonlinear coefficient, attenuation and dispersion. The parameters of input signal could also be arbitrary, i.e. with arbitrary transmission rate, input power, and any duty cycle of RZ pulse. Even the amplification schemes could be single-stage erbium-doped fiber amplifier (EDFA), or double-stage EDFA, or hybrid EDFA-Raman amplification. The database is obtained by numerous numerical simulations, neglecting the amplified spontaneous emission noise, polarization mode dispersion. The performance of transmission system impaired by nonlinear effects is represented by eye opening penalty (EOP). One can use the database to estimate the EOP of single channel transmission systems with bit rate up to 160 Gb/s, and can also evaluate the maximum transmission distance for given system impairment conveniently. For high-bit-rate transmission systems, intra-channel nonlinearity dominates the nonlinear impairments, therefore, the database to asses the nonlinear impairment of single channel transmission link is also valid for high-bit-rate wavelength-division multiplexed (WDM) systems. The accuracy and the limitation of the database are also discussed.