The development of colorimetry relies on the perceptual phenomena and the experimental data. With the increase of experimental data of visual color difference, people tries to explore and develope new color space, which is as simple as the CIELAB color space, but more uniform. The characteristics of CIELAB color space are analyzed, and a color space with four parameters based on these characteristics is proposed, which is called MLAB color space. The determination of the new color space parameters is a nonlinear constrained optimization problem, which can ensure that the optimized space can well predict the COM-corrected visual color difference dataset collected by the expert group of International Commission on Illumination. Comparison based on COM-Corrected dataset shows that MLAB color space is significantly better than CIELAB color space. Tests based on hue linearity and ellipse datasets show that MLAB color space is also improved to a certain extent compared with CIELAB color space.