Recently,　biodegradable　plastics　were　proposed　to　solve　the　issue　of　microplastic　particles（MPs）.　However,　biodegradable　MPs　may　pose　stronger　negative　effects　on　several　soil　species　than　traditional　MPs　under　some　conditions.　Biochar　has　been　widely　used　in　soil　improvement　and　remediation,　but　the　effects　of　biochar　application　on　the　physicochemical　properties　of　the　soil　are　still　limited.　Therefore,　polylactic　acid（PLA）MPs　were　selected　as　the　research　object,　and　a　half-year　soil　culture　experiment　was　conducted　to　analyze　the　effects　of　chicken-manure　biochar　on　the　quality　of　PLA-MP　polluted　soils.　The　results　revealed　that　PLA-MPs　pollution　caused　an　increase　of　soil　pH,　posed　the　loss　of　nutrients（e.　g.,　nitrogen,　phosphorus,　and　potassium）,　and　influenced　the　soil　carbon　turnover.　The　alkalization　of　acidic　soils　and　the　varying　upregulated　activities　of　urease　and　invertase　were　observed　post　chicken-manure　biochar　application.　Furthermore　at　the　end　of　soil　incubation　clear　increase　in　the　available　phosphorus　and　potassium　with　61.08%　and　6.10　times,　respectively,　was　observed　in　PLA-MP　polluted　soils;　however,　a　remarkable　decline　in　inorganic　nitrogen　with　64.31%　was　observed.　Under　the　synergistic　effects　of　PLA-MPs　and　biochar,　the　net　total　carbon　variable　was　significantly　positively　correlated　with　that　of　in　PLA-MPs　polluted　soils.　This　study　demonstrates　that　the　biochar　application　slows　down　the　PLA-MPs　induced　nutrient　loss　and　that　the　soil　total　carbon　turnover　and　nitrogen　transformations　are　synergistically　affected　by　biochar　and　PLA-MPs.　©　2024　Editorial　Board　of　Journal　of　Agro-Environment　Science.　All　rights　reserved.