8-month-old baby platelets low only 30 × 10⁹ / L to be important, easy to lead to spontaneous bleeding, and even life-threatening. Platelets normal value reference range for reference value for (100~300) × 10⁹ / L, if the value in the (25~350) × 10⁹ / L is moderately low. The main functions of platelets are clotting, hemostasis and repair of broken blood vessels. When the platelets are reduced, the patient may have bruises and bleeding spots on the skin and mucous membranes, gastrointestinal bleeding as well as severe intracranial hemorrhage, etc., which may even be life-threatening. Thrombocytopenia in 8-month-old babies may be caused by immune disorders or viral infections, hypersplenism, leukemia, aplastic anemia and other causes of thrombocytopenia. The cause of thrombocytopenia should be clarified in time and targeted treatment should be given.