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Polycrystallized Y1−xCaxBa1.9Nd0.1Cu3Oy (YCBNCO) compounds with x⩽0.40 were synthesized using standard solid state reaction technique. The structure for all samples was characterized by X-ray diffraction with Rietveld refinements. The transport properties for YCBNCO were measured by the standard four-probe method in the temperature range from 20 to 300 K. With the increase of Ca content, the variation of the superconducting transition temperature Tc can be divided into three regions: in the doping region I with x⩽0.10, Tc decreases sharply and linearly with x, which may relate to the competition between Ca2+ and Nd3+; in the region II with 0.10, Tc deviates the fitting line; and in region III with x⩾0.25, Tc decreases slowly with increasing Ca content,which may relate to the formation of the Ca-rich phase. The dependence of resistivity on temperature, and the relation of the structural parameters versus the content of Ca were discussed. The Ca content dependence of the spin-gap opening temperatures in the normal state for YCBNCO was investigated. [Copyright &y& Elsevier]