Context : Linear polarization of diffuse Galactic emission is a signature of magnetic fields in the interstellar medium of our Galaxy .
Observations at high frequencies are less affected by Faraday depolarization than those at lower frequencies and are able to detect polarized emission from more distant Galactic regions .

Aims : We attempt to perform a sensitive survey of the polarized emission from the Galactic disk at \lambda 6 cm wavelength .

Methods : We made polarization observations of the Galactic plane using the Urumqi 25-m telescope at \lambda 6 cm covering the area of 60 \degr \leq l \leq 129 \degr and |b| \leq 5 \degr .
Missing large-scale structures in polarization were restored by extrapolation of the WMAP polarization data .

Results : We present the \lambda 6 cm total intensity and linear polarization maps of the surveyed region .
We identify two new extended H II regions G98.3 - 1.6 and G119.6+0.4 in this region .
Numerous polarized patches and depolarization structures are visible in the polarization maps .
Depolarization along the periphery of a few H II complexes was detected and can be explained by a Faraday screen model .
We discuss some prominent depolarization H II regions , which have regular magnetic fields of several \mu G. Structure functions of U , Q , and PI images of the entire \lambda 6 cm survey region of 10 \degr \leq l \leq 230 \degr exhibit much larger fluctuation power towards the inner Galaxy , which suggests a higher turbulence in the arm regions of the inner Galaxy .

Conclusions : The Sino-German \lambda 6 cm survey reveals new properties of the diffuse magnetized interstellar medium .
The survey is also very useful for studying individual objects such as H II regions , which act as Faraday screens and have high rotation measures and therefore strong regular magnetic fields inside the regions .