Crystal structures and thermal expansion properties of Yb_(2-x)Fe_xMo_3O_(12)(x=0.0,0.6,1.0,1.1,1.4) solid solutions have been studied by X-ray powder diffraction(XRPD) at different temperatures.Rietveld analysis of the XRPD data shows that Yb_(2-x)Fe_xMo_3O_(12) solid solutions adopt orthorhombic structure and have variable thermal expansion coefficients controlled by the ratio of Yb~(3+) to Fe~(3+).Yb_2Mo_3O_(12) shows anisotropic negative thermal expansion property,induced by the reductions in average Yb-O-Mo angle and average apparent Mo2-O bond length with increasing temperatures.As more Yb~(3+) substituted by Fe~(3+),the linear thermal expansion coefficients of Yb_(2-x)Fe_xMo_3O_(12) increase from negative to positive.A near-zero thermal expansion coefficient of 0.55×10~(-6)K~(-1) for Yb_(0.6)Fe_(1.4)Mo_3O_(12) is observed in the temperature range of 573-873 K Solid structure and thermal expansion properties of Yb_ (2-x) Fe_xMo_3O_ (12) (x = 0.0,0.6,1.0,1.1,1.4) solid solutions have been studied by X-ray powder diffraction (XRPD) at different temperatures. (12+). The XRPD data shows that Yb_ (2-x) Fe_xMo_3O_ (12) solid solutions adopt orthorhombic structure and have variable thermal expansion coefficients controlled by the ratio of Yb_ (3+) to Fe_ (3 +). Yb_2Mo_3O_ (12) (3+) substituted by Fe ~ (3 +), the linearity of Yb-O-Mo bond and average apparent Mo2-O bond length with increasing temperatures. thermal expansion coefficients of Yb_ (2-x) Fe_xMo_3O_ (12) increase from negative to positive. A near-zero thermal expansion coefficient of 0.55 × 10 -6 K -1 for Yb_ (0.6) Fe_ ) Mo_3O_ (12) is observed in the temperature range of 573-873 K