The present paper proposes a versatile strategy for the synthesis and mechanical property manipulation of networked biodegradable polymeric materials composed of well-defined alternating soft and hard domains. As an example of the strategy, we selected biodegradable poly(L-lactide) (PLLA) and poly(ε-caprolactone) (PCL) as the hard and soft components, respectively, and synthesized networked biodegradable polymeric materials composed of well-defined alternating PLLA and PCL domains with different L-lactide (LLA) unit contents via crosslinking of well-defined four-armed diblock copolymers of PLLA and PCL (4-C-L). The strategy reported here, which is also applicable to non-biodegradable polymeric materials, successfully facilitated the synthesis of the networked biodegradable materials composed of alternating hard and soft domains and their mechanical properties of the synthesized materials were largely manipulated by the LLA unit contents of the precursor four-armed diblock 4-C-L copolymers. Moreover, the crystallization behavior and thermal properties of 4-C-L copolymers before and after crosslinking were investigated and discussed.