The present disclosure relates to a kit for preparing radio-isotope labeled human serum albumin (HSA) microspheres, which includes: a container (A), containing SnCl2 dissolved in an aqueous acid solution a container (B), containing an acidic substance as a tin salt stabilizer a container (C), containing HSA microspheres to be labeled by a radio-isotope and a container (D), containing a pH adjuster. According to the present kit for quickly preparing radio-isotope labeled HSA microspheres, HSA microspheres can be simply and quickly labeled by a radio-isotope at high labeling efficiency.The present disclosure also relates to a method for quickly preparing radio-isotope labeled HSA microspheres by using the kit.
