The invention discloses a preparing method of a modified gingko testa-alginate microsphere adsorbent. The method comprises the steps that firstly thoroughly washed gingko testa is smashed, then the smashed gingko testa is added into an alkaline solution of diamine or polyamine, centrifugation is conducted after a reaction is conducted for a certain time, centrifugate and a phenol compound are reacted for a certain time and are then concentrated, then a certain amount of polymers is added, and the polymers and an alginate solution are mixed together, under stirring, a calcium chloride solution is injected, and the modified gingko testa-alginate microsphere adsorbent is prepared. The preparing method is simple in process, convenient to operate, controllable in technology, mild in condition, good in repeatability, low in cost and easy to apply and popularize, the prepared modified gingko testa-alginate microsphere adsorbent has good performance of adsorbing heavy metal ions and organic pollutant, further has certain innovative significance in reducing pollution and cleaning the environment, and has a wide application prospect.