The invention provides a bismuth micron particle. The particle is a bismuth elementary substance, the particle size of the particle is 1 micron to 3 microns, and the particle is spherical or polyhedral. The method for manufacturing the particle comprises the following steps that a bismuth source and template agents are added to glycol and stirred to be completely dissolved, then the pH value of a solution is adjusted to be larger than 10 while stirring is carried out, after solute is completely dissolved, the solution is transferred into a closed polytetrafluoroethylene lining high-pressure reaction still, a reaction is carried out for more than 10 h under the condition of 160 DEG C to 200 DEG C, a product is centrifuged or filtered after the reaction is finished, residual solute is removed through washing, and the bismuth micron particle can be obtained through drying and cooling. The positive colossal magnetoresistance of the bismuth micron particle is more than 700 percent at low temperature, the positive colossal magnetoresistance of the bismuth micron particle is more than 180 percent at indoor temperature, and the manufacturing method of the bismuth micron particle is simple.