An　MG-200　high　speed　and　high　temperature　friction　and　wear　tester　was　performed　to　evaluate　the　friction　and　wear　behaviors　of　AISI1045　steel　sucker　rod　sliding　against　J55　tubing　string　and　J55　tubing　strings　coated　with　spray-welded　wear-resistant　coatings　of　various　thickness　in　a　ring-on-ring　configuration　and　under　the　lubrication　of　oil-field　wastewater　as　the　lubricating　medium.　The　worn　surface　morphologies　of　the　steel　sucker　rod　specimens　coupled　with　the　J55　tubing　string　and　the　J55　tubing　string　coated　with　the　wear-resistant　coating　were　observed　using　a　scanning　electron　microscope.　As　the　results,　it　was　effective　to　increase　the　wear-resistance　of　the　frictional　pair　by　introduction　of　the　wear-resistant　coatings　on　the　tubing　string　surface.　The　wear-resistant　coating　of　a　proper　thickness　also　contributed　to　reduce　the　friction　coefficient　to　some　extent,　which　was　helpful　to　reducing　the　friction　force　between　the　sucker　rod/tubing　string　pair　and　increasing　the　service　lifetime　of　the　pair.　The　decreased　wear　rates　of　the　sucking　rod　specimens　coupled　with　the　tubing　string　specimens　coated　with　the　wear-resistant　coating　of　a　proper　thickness　were　attributed　to　the　action　of　the　coating　in　decreasing　adhesion　wear.　Moreover,　the　tubing　string　specimen　recorded　little　difference　in　wear　rate　at　room　temperature　and　60°C.　However,　the　sucker　rod　specimen　registered　a　slightly　larger　wear　rate　at　60°C　than　at　room　temperature,　which　could　be　attributed　to　the　enhanced　adhesion　wear　and　mild　corrosive　wear　at　elevated　temperature.　It　was　imperative　to　properly　control　the　thickness　of　the　wear-resistant　coating　on　the　tubing　string　surface　so　as　to　bring　its　friction-reducing　and　antiwear　action　into　effect.