The invention discloses a composition for solid precipitation and inhibition of an oil and gas well. The composition for solid precipitation and inhibition per 100 parts by weight is prepared from the following components: 0.08 to 0.13 part by weight of ferrocyanide, 0.005 to 0.02 part by weight of a polyether type surfactant, 0.005 to 0.02 part by weight of a hydrophobic modified cationic polymer and the balance of water. The composition can be put in the oil and gas well with hypersalinity; the ferrocyanide can be used for changing the charge distribution on the surface of metal cations, and the hydrophobic modified cationic polymer can be used for adsorbing anions in hydrops of the oil and gas well, so that the metal cations such as sodium ions can be prevented from being combined with the anions to form inorganic salts so as to be separated out from the hydrops of the oil and gas well, and the inhibition rate is 90 percent or more; the polyether type surfactant can be directionally adsorbed on the surface of hydrocarbon organisms such as paraffin, a polar surface can be formed, non-polar hydrocarbon organisms such as paraffin crystal can be prevented from being continuous crystallized and separated out, and the inhibition rate is 53 percent or more; the ferrocyanide, the hydrophobic modified cationic polymer and the polyether type surfactant can promote each other and are capable of commonly inhibiting the inorganic salts and the hydrocarbon organisms such as the paraffin from being separated out.