We report on the Suzaku results of the mixed-morphology supernova remnant ( SNR ) G290.1 - 0.8 ( MSH 11-61A ) .
The SNR has an asymmetric structure extended to the southeast and the northwest .
In the X-ray spectra of the center and the northwest regions , we discover recombining plasma features with the strong Si Ly \alpha and radiative recombination continuum at \sim 2.7 keV .
These features are the most significant in the northwest region , and the spectra are well-reproduced with a recombining plasma of kT _ { e } = 0.5 keV .
Whereas the spectra of other regions are expressed by an ionizing plasma of kT _ { e } = 0.6 keV .
The recombining plasma has over-solar abundances , while the ionizing plasma has roughly solar abundances .
Hence they are likely ejecta and interstellar medium ( ISM ) origin , respectively .
The recombining plasma in the northwest of G290.1 - 0.8 would be generated by a break-out of the supernova ejecta from a high density circumstellar medium to a low density ISM .