We report the confirmation of a TESS-discovered transiting super-Earth planet orbiting a mid-G star, HD 307842(TOI-784). The planet has a period of 2.8 days, and the radial velocity (RV) measurements constrain the mass to beM9.67 0.820.83-+ Å. We also report the discovery of an additional planet candidate on an outer orbit that is most likelynontransiting. The possible periods of the planet candidate are approximately 20–63 days, with the correspondingRV semiamplitudes expected to range from 3.2 to 5.4 m s−1 and minimum masses from 12.6 to 31.1 M⊕. Theradius of the transiting planet (planet b) is R1.93 0.090.11-+ Å, which results in a mean density of 7.4 g cm1.21.4 3-+ -suggesting that TOI-784 b is likely to be a rocky planet though it has a comparable radius to a sub-Neptune. Wefound TOI-784 b is located at the lower edge of the so-called “radius valley” in the radius versus insolation plane,which is consistent with the photoevaporation or core-powered mass-loss prediction. The TESS data did not revealany significant transit signal of the planet candidate, and our analysis shows that the orbital inclinations of planet band the planet candidate are 88.60 0.860.84-+ and 88°.3–89°.2, respectively. More RV observations are needed to determine the period and mass of the second object, and search for additional planets in this system