AbstractSolid‐state lithium metal batteries (SSLMBs) are identified as a highly promising candidate for next‐generation energy storage devices, yet they still face uncontrollable dendritic lithium (Li) growth originating from interfacial incompatibility. To address this issue, an “integration plasma (IP)” strategy for interlayer construction is proposed that integrates metal reduction and vapor deposition functions, featuring the ability to give a manipulable and quantifiable chemical regulation for controlling the surface concentration (C_surface) and the atomic ratio of the introduced metal element and electronegative element (AR_E/M) on solid‐state electrolyte (SSE). This IP‐formed interlayer can in situ react with Li anode to synchronously produce metal‐Li alloy, Li salt and amorphous carbon, thus offering an “integrated function” to promote a spherical and hexagonal Li growth, preventing the dendrite propagation from SSE. When C_surface of metal elements and corresponding AR_E/M is regulated as ≈1.13 nmol cm^‐2 and ≈2.6, the IP‐modified SSE prolongs the lifespan of SSLMBs with LiNi_0.8Co_0.1Mn_0.1O₂ cathode to over 1000 cycles with a low‐capacity attenuation of 0.03% per cycle, highlighting the multiply functions of IP to accelerate the practical application of SSLMBs.