Precision medicine has shown a new hope for cancer treatment because it can provide clear individual disease causes, precision therapeutic targets and accurate classification based on the genome sequencing, bioinformatics, and large database. However, the effective precision therapy should also include how to deliver and release drugs with controlled dosage at the precision therapeutic targets. A challenge in clinical anti-tumor precision therapy is how to achieve precision delivery and regulate the dosage of screened drugs, including how to overcome the biological barrier, how to safely deliver the drugs to nidus, how to enhance intratumoral accumulation of drugs, how to promote endocytosis of target cells, and how to accurately deliver drugs to intracellular therapeutic targets. Nanomedicine can effectively solve the problems as mentioned above. Through fine design and nanocarrier tailoring, nano-products will accurately and efficiently deliver the screened drug molecules to target organs, target tissues, target cells or intracellular target organelles, and precisely release the drug to a desirable dosage under the stimulation of lesions. The combination of precision medicine and nanomedicine can efficiently achieve precision therapy: from the tumor molecular classification, drug screening, drug precision delivery, controlled drug release to the treatment. Consequently, precision medicine mainly refers to accurate diagnosis and accurate screening of drug targets, which is the so called "advance troops and scouts" of precision treatment of cancer. Nanomedicine mainly focuss on the accurate delivery and controlled release of drugs to the therapeutic target, which can be called "accurate strategic bombing". Both precision medicine and nanomedicine are essential and interdependent elements in precision therapy.