The ring opening (

co

-)polymerization of

ε

-caprolactone or/and lactides produces the biodegradable polymers. Targeting the cost reduction and non-toxicity of its catalysts to meet the demanding for food packaging polymer

the ferric chloride with its initiator of 1-tetradecanol are currently explored in the ring opening (

co

-) polymerization of

ε

-caprolactone or/and

L

-lactide. Results approve the good efficiency of FeCl

3

in ring opening polymerizing of

ε

-caprolactone

and the polymerization parameters (such as molar ratio of monomer to iron

temperature and time) are useful in controlling the polymerization efficiency and resulting in polymers with different molecular weights. Extensively the catalytic system is also well active for the polymerization of

L

-lactide as well as copolymerization of

ε

-caprolactone and

L

-lactide; the feeding order of monomers (

ε

-caprolactone and

L

-lactide) and polymerization greatly influenced the microstructures of resultant polymers. The blocked copolymer

PCL-

b

-PLA can be only prepared with adding the first

ε

-CL and then LA. In addition

the stoichiometric amount of compounds acting as N

N-bidentate ligands is added in FeCl

3

catalytic system

in situ

to influence the polymerization and adjust the molecular weight of polymers

in turn to realize the controllable polymerization.