A safe and convenient disposable blood-taking needle with double-surface cap, including lancet body with needle tip, lancet handle and lancet cap. Lancet body is fixed inside lancet handle and needle tip extends out of first end of lancet handle to be inserted into lancet cap, wherein: body of lancet cap is a block structure, which includes first and second faces. Both first and second faces are flat and opposed when one face faces upwards, the other face faces downwards and the included angle between them in space is less than 45°； first face is provided with first blind hole and second face is provided with second blind hole and both first and second blind holes match first end of lancet handle in respect of connection relationship. In block structure, except the first and second faces, other external surfaces are arcuate faces protruding outward and/or angular faces protruding outward.
