A bi-profiled fiber and preparing method thereof are provided. The bi-profiled fiber is manufactured through the steps of spinning melt metering, extruding via the composite spinneret, cooling, oiling, drawing, heat setting and winding, finally containing both double-cross monofilaments and circular monofilaments simultaneously. The bi-profiled fiber is made of the modified polyester, and the modified polyester is dispersed by matte agent and is composed of terephthalic acid segments, ethylene glycol segments and branched diol segments, and the branched diol segment has a structural formula of where R1 and R2 are separately selected from the linear alkylene with 1-3 carbon atoms, R3 from the alkyl with 1-5 carbon atoms, and R4 from the alkyl with 2-5 carbon atoms. The matte agents is a mixture of amorphous titanium dioxide and amorphous silicon dioxide, or a mixture of calcium carbonate and amorphous silicon dioxide.