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We synthesized SrWO:Ho, Yb, Tm microspheres successfully by the solvothermal process. The samples were characterized by XRD, FTIR, SEM, and fluorescence spectrofluorometer. The XRD patterns and FTIR spectra indicate that the samples have the pure tetragonal scheelite structure. The SEM images suggest that Na-Citrate plays a key role in the formation of spherical morphology. The samples are microspheres if there is the use of Na-Citrate, whereas the samples are irregular particles if there isn't the use of Na-Citrate. Under diode laser excitation of 980 nm, SrWO:Ho, Yb, Tm samples show blue, green, and red emissions originating from the transitions of Ho and Tm ions. The emission intensity of microspheres is about twice those of irregular particles. The emission shows clear dependence on pump powers. On the basis of the luminescence properties of SrWO:Ho, Yb, Tm phosphors, the possible mechanisms are speculated. [ABSTRACT FROM AUTHOR]