Compared　with　the　traditional　current　transformer　with　magnetic　core,　Rogowski　coil　has　more　advantages,　such　as　non-saturation,　high　measurement　accuracy,　wide　measurement　range,　simple　fabrication　technique　and　low　cost.　In　recent　years,　Rogowski　coil　become　an　extremely　popular　method　of　measuring　current　in　power　grid.　Rogowski　coil　is　widely　used　to　measure　three　-　phase　current　in　circuit　breaker　space.　However,　Rogowski　coil　brings　the　problems　of　low　mutual　inductance　and　phase　angle　difference.　Integral　circuit　can　address　the　issue　of　phase　angle　difference.　But　Rogowski　coil　with　low　mutual　inductance　has　low　signal-to-noise　ratio　and　vulnerable　to　interference　from　external　magnetic　field.　The　design　of　Rogowski　coil　with　large　mutual　inductance　and　integral　circuit　is　required.　This　paper　theoretically　analyzes　how　to　design　a　PCB　Rogowski　coil　with　many　turns　and　large　mutual　inductance　in　the　limited　space.　A　modified　integral　circuit　with　excellent　amplification　and　integration　is　proposed.　Although　the　PCB　Rogowski　coil　designed　in　this　paper　only　occupies　1.435cm(3)　in　volume,　the　value　of　mutual　inductance　is　89nH.　The　output　voltage　of　PCB　Rogowski　coil　is　0.023mV/A.　In　the　range　of　50Hz-1kHz,　the　integration　and　amplification　of　the　circuit　is　reliable.　The　amplitude　of　the　integral　circuit　is　62.2dB　at　power　frequency　and　the　crosstalk　coefficient　of　the　PCB　Rogowski　coil　is　no　more　than　0.26%.　The　temperature　drift　of　the　modified　integral　circuit　is　less　than　0.16%　and　has　no　influence　on　the　measurements.