Space breeding is a kind of physical radiation breeding. The change of mutants is the result of their own gene mutation，and does not involve the introduction of exogenous or endogenous genes. The changes induced by space environment factors on spaceflight are exactly the same as the mutations in plant nature and are not the product of artificial genetic engineering technology. The radiation dose of space radiation is very low，and it is not passed on to the next generation of materials，let alone radioactive. Physical radiation breeding has a history of nearly 100 years in the world，and there are more than 3000 commercially released varieties. Practice has proved that there is no case of food safety or environmental ecological harm. Space breeding has a history of 34 years in China. More than 200 main grain crop varieties，including rice，wheat，corn and soybean，have only passed provincial and national examination. The planting area and consumption level are very considerable，and there has never been any food safety problem. Astronauts on the International Space Station have harvested fresh vegetables that can be eaten directly，further proving the safety of space-bred food. Similar experiments on space plant culture will be carried out after the completion of China’s space station. Gradually promoting and improving the scientific literacy of the public and popularizing the scientific knowledge can help to eliminate the misunderstanding and misreading of the safety of space breeding products，and to clear up the sources and eliminate the influence of rumors and grounders.