We have carried out ^ { 12 } CO J =2-1 and ^ { 12 } CO J =3-2 observations toward the high-mass protostellar candidate IRAS 20188+3928 .
Comparing with the previous observations , the ^ { 12 } CO J =2-1 and ^ { 12 } CO J =3-2 lines both have asymmetric profiles with an absorption dip .
The velocity of the absorption dip is \sim 1.0 km s ^ { -1 } .
The spectral shape may be caused by rotation .
The velocity-integrated intensity map and position-velocity diagram of the ^ { 12 } CO J =2-1 line present the obvious bipolar component , further verifying this region has an outflow motion .
This region also is associated with an HII region , an IRAS source , and H _ { 2 } O maser .
The H _ { 2 } O maser has the velocity of 1.1 km s ^ { -1 } .
Comparing with the components of the outflow , we find that the H _ { 2 } O maser is not associated with the outflow .
Using the LVG model , we obtained that possible averaged gas density of the blueshifted lobe and redshifted lobe are 1.0 \times 10 ^ { 5 } cm ^ { -3 } and 2.0 \times 10 ^ { 4 } cm ^ { -3 } , while kinetic temperature are 26.9 K and 52.9 K , respectively .
Additionally , the outflow has the higher integrated intensity ratio ( I _ { CO } _ { J = 3 - 2 } / I _ { CO } _ { J = 2 - 1 } ) .