You will see this sign in almost every hospital or clinic in China. It is the first stop when you go to see a doctor in a hospital. At this place a patient will be asked to pay a small fee (like copay in a U.S. hospital or clinic) and be directed/appointed to doctors based on his/her symptoms.
In China, hospital or clinic visit works similarly to walk-in clinics in the U.S. You don't need to make an appointment with a doctor in advance, except for seeing a specialist. You can just go there whenever you feel you need to.