A non-volatile resistive random access memory (RRAM) device with a Cr-doped SrZrO3/SrRuO3 bottom electrode heterostructure was fabricated on SrTiO3 substrates using pulsed laser deposition. During the deposition process, the substrate temperature was 650oC and the variable ambient oxygen pressure had a range of 50-250 mTorr. The sensitive dependences of the film structure on the processing oxygen pressure are important in controlling the bistable resistive switching of the Cr-doped SrZrO3 film. Therefore, oxygen pressure plays a crucial role in determining electrical properties and film growth characteristics such as various microstructural defects and crystallization. Inside, the microstructure and crystallinity of the Cr-doped SrZrO3 film by oxygen pressure were strong effects on the set, reset switching voltage of the Cr-doped SrZrO3. The bistable switching is related to the defects and controls their number and structure. Therefore, the relation of defects generated and resistive switching behavior by oxygen pressure change will be discussed. We found that deposition conditions and ambient oxygen pressure highly affect the switching behavior. It is suggested that the interface between the top electrode and Cr-doped SrZrO3 perovskite plays an important role in the resistive switching behavior. From I-V characteristics, a typical ON state resistance of 100-200 Ω and a typical OFF state resistance of 1-2 kΩ, were observed. These transition metal-doped perovskite thin films can be used for memory device applications due to their high ON/OFF ratio, simple device structure, and non-volatility.