The engineering background of the development of low Cr tubing and casing was presented in this paper. The resistance of low Cr tubing and casing against CO2/H2S corrosion was summarized. The effects of various factors, such as Cr content, pH value, temperature, flow velocity, etc., on corrosion behavior of low Cr steel and surface characteristics of corrosion scales in the environment containing sweet gas (only CO2) were reviewed in details. Besides, the corrosion characteristics in the environment containing acidic gas (H2S) and the resistance performance on sulfide stress cracking (SSC) of low Cr steel were also elaborated. And the CO2 corrosion mechanism and H2S corrosion mechanism of low Cr steel were also discussed respectively. The studies found that low Cr steel had good resistance against CO2/H2S uniform corrosion owing to the enrichment of Cr element in corrosion scales, the amorphous Cr(OH)3 formed in the corrosion scales, so corrosion scale had the permselectivity towards cations, reducing anion concentrations at the interface between corrosion scales and metal substrate. And at the same time, the local corrosion was suppressed, especially pitting corrosion, owing to the decreasing possibility of Cl? reunion and nucleation at the interfaces. However, the mass percent of Cr element in the matrix should be not lower than 3% to further suppress or eliminate pitting corrosion. The resistance against SSC was further enhanced owing to the precipitation and diffuse distribution of Cr element in the form of granular carbides in the grain boundary and inside the grains. Meanwhile, the application status of low Cr tubing and casing in oil & gas fields was mentioned. At last, the potential development was prospected. Economical low Cr tubing and casing against CO2/H2S corrosion represents the future development trend, which will be obtained from the quaternity method of chemical composition, technology, structure, and performance of steel.